def f(n):
    if  n <=1:
        return 1
    else:
        return n*f(n-1)

num =int (input('一个正整数'))
s=f(num)
print(num,'的阶乘',s)

def su(n):
    if n ==1:
        return 1
    else:
        return n +su(n-1)

print(su(100))

def fibo(n):
    if n <=2:
        return 1
    else:
        return fibo(n-1)+fibo(n-2)
print('第{}项为{}'.format(7,fibo(7)))

sum=lambda a,b,c,:a+b+c
print(sum(1,2,3))
fun=lambda m:m**2
print(fun(5))


